Intersystem Link Protocol (ISLP) datagrams represent a form of encrypted data, typically used for secure voice communications. When ISLP data is transmitted in a data stream across a bearer network, other network infrastructure devices in the bearer network that may process the data stream must be informed so that they don't process the data and corrupt the encrypted ISLP datagrams. The devices can be externally controlled to start a “clear-channel” mode of operation without processing of the data.
Existing solutions are able to provide guidance via control/signaling messages sent out of band to the network infrastructure devices where the ISLP protocol is implemented to direct when to enable/disable clear-channel support. The control/signaling messages will then be processed, and signal processing blocks such as Echo Cancellation (EC) and Voice Quality Enhancement (VQE) modules can be disabled. However, in internet protocol (IP) networks, there are potentially multiple network infrastructure devices in the network that do not have any knowledge of the content in the data stream, and are not communicated to/with the control/signaling messages. Therefore, there is no way to inform these network infrastructure devices of their need to enter/exit a clear-channel mode of processing.